Sorry, I meant cellular physiology - something mysterious and sci-fi-y going on at the microscopic level (storing enormous amounts of energy, or some such).

Basically, if Supes can bench press an asteroid, the force imparted by the physical size of his deltoids is all but irrelevant. It’s the “yellow Sun business” that’s doing all the work. So that same asteroid would be no problem for Supergirl either.

In a fight between a Kryptonian male and female (where each is capable of punching the other across the Grand Canyon), I think it would take a very specific circumstance where intrinsic/normal strength would factor into the match as a significant “advantage.”